The wife of Malaysian PM Mahathir Mohammad has said couples should space out the births of their children because over-crowding can lead to incest, the New Sunday Times reported. Siti Hasmah Mohd Ali said couples should consider whether their house had enough room for a large family and take into consideration income and living conditions. ‘‘They can still have large families, but the birth of children should be spaced out as it is not proper for one whole family to share one bedroom,’’ she said. Mostly Muslims in Malaysia plan to impose harsher sentences on offenders after a series of incestuous rapes involving children. Official statistics show a total of 1,221 incest cases were reported in Malaysia between 1998 and July 2002. Reports of fathers raping daughters have become common. Mahathir said earlier this week he felt sad and ashamed over the high incidence of sexual offences in Malaysia.